报错如下：

								# pip 
							
								Traceback ( most recent call last ) : 
							
								   File "/usr/bin/pip" , line 5 , in < module > 
							
								     from pkg_resources import load_entry_point 
							
								ImportError : No module named pkg_resources

其实发生这个问题是因为：虽然你已经把Python升级到了2.7版本，但是pip仍然是原来的，版本，仍然在原来python的site-package里面

解决方法：

重新安装pip

curl -O https://pypi.python.org/packages/source/p/pip/pip-7.1.2.tar.gz
用wget下载时会报错，这里改用curl -O
tar zxvf pip-7.1.2.tar.gz     
cd pip-7.1.2    
python setup.py install
ln -s /usr/local/python27/bin/pip2.7 /usr/bin/pip  #创建软链接时报文件已经存在时执行rm -rf /usr/bin/pip
//pip默认安装到了/usr/local/python27/bin下面

测试pip

[root@localhost pip-7.1.2]# pip list
distribute (0.6.14)
pip (7.1.2)
setuptools (0.6rc11)
wheel (0.29.0)
The directory '/root/.cache/pip/http' or its parent directory is not owned by the current user and the cache has been disabled. Please check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag.
/usr/local/python27/lib/python2.7/site-packages/pip-7.1.2-py2.7.egg/pip/_vendor/requests/packages/urllib3/util/ssl_.py:90: InsecurePlatformWarning: A true SSLContext object is not available. This prevents urllib3 from configuring SSL appropriately and may cause certain SSL connections to fail. For more information, see https://urllib3.readthedocs.org/en/latest/security.html#insecureplatformwarning.
  InsecurePlatformWarning
You are using pip version 7.1.2, however version 9.0.1 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.

【Python】升级python至2.7后pip不可用